1. Field of the Invention
The present disclosure relates to fans, and more particularly to turbofans for gas turbine engines, for example.
2. Description of Related Art
A gas turbine engine typically includes a compressor section, a combustor section, and a turbine section. In the case of a turbofan, the engine also includes a fan section. Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-speed exhaust gas flow. The high-speed exhaust gas flow expands through the turbine section to drive the compressor and the fan section.
The fan section drives air through a core passage and a bypass passage. The ratio of flow through the bypass passage versus through the core (compressor and turbine) is called the bypass ratio. There is a trend toward larger and larger bypass ratios. For example, in a geared turbo fan (GTF) engine, a gearing system is used to connect the driving shaft to the fan section, so the fan can rotate at a different speed from the turbine driving the fan. One aspect of this type of engine is a larger bypass ratio than previous turbofan engines. As bypass ratio increases, the flow efficiency through the fan and bypass passage is increasingly becoming a key factor in overall engine performance.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for systems and methods that allow for improved flow efficiency in fans and bypass passages. The present disclosure provides a solution for these problems.